Torque Converter

[medivh25]

Hello guys,

I have recently rebuilt the Transmission in my 97 blazer. I Have everything reinstalled and running. The transmission shifts great, up and down, locks up fine also..

My question is this, at idle I have a strange vibration that kinda oscillates if that makes since at all. Example, thinking of a clock spinning around, the vibration only happens between 6-9 oclock it's smooth between 10-5.

No noise under or around the truck, but you can feel the vibration in the pedals and hear it in the cab. TC is a cheep new one. I have right around 175 miles on the transmission now. Any ideas?

Thank you,
Dusty

[cahall]

Does the vibration ever go away? Does it get worse, better or stay the same if you brake stall it?

Frank

[Mystery Bird]

Two thought come to mind: loose TC bolt or crack in the flywheel.

[medivh25]

The vibration does not seem to be constant, more prevalent at lower rpms. I have not tried a stall test yet will do that today.. This vibration was not present before the rebuild. Hard for me to explain it in words, but its kinda a vibration slash groan you can feel....

Bolts could be loose I guess but I used locktite and torqued em down 30 pounds or so..

Thank you for the help!!

[cahall]

One way to check if it's a converter is to unbolt it from the fleplate and slide it back. If the vibration isn't there with it unbolted then you might want to consider the converter is out of balance. Torque converters are balanced just like a tire. You add weight to the light area..

Frank

[medivh25]

Thank you Cahall During the stall test nothing seemed out of the ordinary, no vibrations or anything. Guess the next step will be to unbolt the TC

[Dynamic396]

Originally Posted by cahall

One way to check if it's a converter is to unbolt it from the fleplate and slide it back. If the vibration isn't there with it unbolted then you might want to consider the converter is out of balance. Torque converters are balanced just like a tire. You add weight to the light area..

Frank

This is exactly what I was going to suggest... Frank beat me to it! Sounds like you got a bad converter.

[Workman]

Yea it does sound like a bad TC, If you want to spend a little extra money Jump to a stall converter if they have that for your vehicle. If your planning on building on it that is.

[Dynamic396]

Originally Posted by Workman

Yea it does sound like a bad TC, If you want to spend a little extra money Jump to a stall converter if they have that for your vehicle. If your planning on building on it that is.

Every torque converter has a stall speed, it's just a matter of what rpm it stalls at. Unless you're planning big mods to the Blazer, I'd stick with the stock stall speed. The stock stall speed for a 4.3 S-10 Blazer is about 1600-1800 rpm. (I had the unfortunate privilege of doing two 4.3 transmissions this week - one Blazer, one Astro van...)

Overstalling a vehicle that doesn't need it is nothing short of annoying after about 15 minutes...

[KW Baraka]

Originally Posted by Workman

Yea it does sound like a bad TC, If you want to spend a little extra money Jump to a stall converter if they have that for your vehicle. If your planning on building on it that is.

WHat exactly is a "stall" converter......and how is it different from a 'torque' converter?

KW

[95Z]

Originally Posted by Dynamic396

...Overstalling a vehicle that doesn't need it is nothing short of annoying after about 15 minutes...

Not to mention the excess heat especially if you plan on towing.

[Dynamic396]

Originally Posted by 95Z

Not to mention the excess heat especially if you plan on towing.

Absolutely. Not only would it create heat like the end of the world was coming, but it wouldn't get out of its own way...

On almost every Ford and Dodge diesel transmission that I build (and I build a ton of them), I actually lower the stall speed by about 250-300 rpm - that is, if the customer can afford it... Lowering the stall speed takes better advantage of the low-end torque that the diesels produce.

Torque converter stall speed is all about where the torque is produced. You must choose wisely...!

[medivh25]

yea definitely keeping the blazer stock. MY Trans am will get the mods

[Workman]

I was saying yea get a lower stall speed tq converter it might help with the rattling, my gpa has one in his old trans am that has a 454 wildcat, the original tq converter was just making it hard on you at idle, bcuz the car would shake hard, and vibrate, but then he got a good stall converter and the car literally stopped shaking, and vibrating at idle.

[Workman]

And he still as that same car to this very day no problems at all out of it. This was several years ago.